Flexible valve seat construction



June 20, 1944. M, w H ET AL 2,352,047

FLEXIBLE VALVE SEAT CONSTRUCTION Filed Oct. 30, 1941 2 Sheets-Sheet lWITNESSES: INVENTORS [I Art/7w M, Wa/zl and Freda-Zak? .1'072725022.

W BY M KTTORN Eg June 20, 1944. A. M. WAHL ET AL FLEXIBLE VALVE SEATCONSTRUCTION FiledOot. 50, I941 2 Sheets-Shee t 2 wnNEssEs;

Patented June 20, 1944 FLEXIBLE VALVE SEAT CONSTRUCTION Arthur M. Wahl,Wilkinsburg, and Frederick B.

Johnson, Clairton, Pa., assignors to Westinghouse Electric &Manufacturing Company, East Pittsburgh, Pa., a corporation ofPennsylvania Application October 30, 1941, Serial No. 417,146

12 Claims.

This invention relates generally to valve constructions and, asspecifically illustrated in this specification, concerns improvements inthe valve construction of compressed gas circuit breakers. Morespecifically, the present invention concerns improved resilient valveseats and is here illustrated as applied to the valve seat constructionof the gas blast type of circuit interrupter, said circuit interrupteremploying compressed gas to extinguish the arc drawn on the contacts ofsaid interrupter when it is opened.

Circuit interrupters which are operated by compressed air or other gasesare very common. The compressed air or other gas is used to open thecircuit interrupter quickly when valves controlling the air or other gasare operated. Frequently the gas is also used to help extinguish the areproduced when the circuit interrupter is opened. In suchan applicationof the gas there must be provided suitable valves which open and closeautomatically in response to the opening and closing of the circuitinterrupter. It is a diflicult problem to provide a valve constructionin such a circuit interrupter which will be reliable, respond quickly,the valve not sticking to the seat, and after many operations remaininggas tight. Since the moving parts of such circuit interrupters aregenerally heavy, the kinetic energy stored in'themoving parts duringrapid operation of said interrupters is high. When the moving parts arebrought to a quick stop,

, stresses and strains'are present in the materials in a gas blast typecircuit interrupter. However,

novel resilient seat for a valve. The consequence of th present novelvalve construction is to permit a dissipation of'the considerable amountof kinetic energy'stored in the rapidly moving valve when it strikes thevalve seat, thus eliminating a permanent deformation of the valve andvalve seat and a resulting leakage of gas through the valve.

Other objects and advantages will become ap parent in the followingdescription when considered in conjunction with the accompanyingdrawings, in which:

Figure 1 is a side elevational view, partly in section, of a gas blasttype of circuit interrupter employing one modification of the presentinvention. The illustrated circuit interrupter in Fig. 1 is more fullydescribed in an application of A. H. Bakken, Serial No. 313,745, filedJanuary 13, 1940, now '0'. S. Patent No. 2,282,154, issued May 5, 1942,and assigned to the assignee of the instant application. It is alsodescribed more completely in an application of R. C. Cunningham and B.P. Baker, Serial No. 357,686, filed September 21, 1940, now U. S. PatentNo. 2,294,824, issued September 1, 1942, and assigned to the assignee ofthe instant application;

Fig. 2 is an enlarged side elevational view, partly in section, of thevalve construction shown in Fig. 1;

Fig. 3 is an enlarged elevational view, partly in section, of amodification of the present invention; and

Fig. 4 is an enlarged elevational view, partly in section, of stillanother modification of the present invention.

Referring to the drawings, particularly to Fig. 1, the reference numeral1 designates a tank for storing gas, such as air, under pressure.Extending from the upper end of the tank I is a relatively short flangedconduit 9 which, in turn, carries a valve casing Secured to the upperend of the valve casing II is a tubular insulator l3 which has securedto its upper end an in sulating support I5. The insulating support l5may be given additional support by an insulating member ll. The supportl5 carries a stationary contact assembly H! which is enclosed within anarc extinguishing structure 2|. The are extinguishing structure 2| is ofconventional design.

Coacting with the stationary contact assembly I9 is a movable contact 23which is preferably of blade-like construction and generally 0- shaped,and mounted for swinging movement about a ivot 25 carried by aconducting bracket 21. External circuit connections to the interrupterare made through a pair of terminal members 29 and 3|, the first ofwhich is secured to the stationary contact assembly I9, and the secondone of which is connected to the conducting bracket 21. Thus, when theinterrupter is in the closed circuit position as is shown in Fig. 1, anelectrical circuit is established between the terminals 29 and 3|through the stationary contact Hi, the movable contact 23 and theconducting bracket 21.

The movable contact 23 is actuated to open and closed circuit positionsby an insulating operating rod 33 actuated by a crank arm 35 carried bya shaft 31, in turn iournaled in a suitabl bracket 39. The shaft 31 isactuated by a crank arm 41 coupled by suitable linkage 43 to theconnecting rod 45 of an air or gas actuated piston operated within thecylinder 41. The connecting rod 45 may be moved up and down to efiectthe respective closing and opening movement of the movable contact 23 bythe admission of compressed gas from the tank I through solenoidoperated valves 49 and 5|. Mechanically operated valves could, ofcourse, be used in place of th solenoid operated valves 49 and i.

The tubular insulator 13, in addition to serving as a support, alsoprovides a passage for trans mitting an arc extinguishing blast of gasfrom the storage tank I to the space between the contacts I9 and 23.This gas blast passage proceeds through the short conduit 9, through thevalve casing H, through the tubular insulator l3, and opening 53 throughthe insulating support l5 which is preferably coextensive with thepassage within the tubular insulator I3.

In the event the moving contact 23 is moved to the open circuit positionWhile the circuit interrupter is carrying load, an arc will be drawnacross the upper end of passage 53 and will be subjected to .a blast ofarc extinguishing gas caused to flow through the tubular insulator l3,whereby the arc will be extinguished. Control of the blast of gas to tharc may be obtained by a valve 55 disposed in the lower end of the valvecasing I I. The valve 55 has a stem El oper- 1 atively coupled to oneend of an actuating member 59. The actuating member 59 is rigidlysecured to a rock shaft 6i journaled in the side of the valve casing H.The shaft 6| extends exteriorly of the casing II, and is actuated bysuitable mechanism, indicated generally by the reference numeral 63, sothat valve 55 opens only during a part of the opening movement of thecircuit interrupter. Consequently, the are drawn on the contacts l9 and23 of the circuit inter-- rupter during the opening movement thereoi issubjected to a blast of are extinguishing gas from the storage tank I.

The mechanism, indicated generally by the reference numeral 63, isactuated :by a cam which is an integral part of the crank arm Thedetails of mechanism 63 are not a part of the present invention. Thesedetails are fully set forth and are claimed in an application of R. C.Cunningham and B. P. Baker, Serial No. 357,686, filed September 21,1940, now U. S. Patent No. 2,294,824, issued September 1, 1942, andassigned to the assignee of the instant application. It sufllces here tosay that the mechanism 63 operates to open valve 55 only during a partof the opening movement of the circuit interrupter. This mechanismoperates to open valve 55 and permit the flow of arc extinguishing gaseven where the contacts, closed under overload conditions, are againmoved to the open position through relay action without having touchedeach other.

The gas blast type of circuit interrupter, illustrated in Fig. 1, isshown to indicate the type of electrical apparatus upon which it ispossible to use the present invention. The present invention can,however, be used on any apparatus which employs valves for fluidcontrol.

Fig. 2 is an enlarged side elevational view, partly in section, of thevalve construction shown in Fig. 1. Referring to Fig. 2, which showsmore clearly than Fig. l the novel valve construction of the presentinvention, there is provided a valve 55 so designed as to have increasedweight and strength. Three spaced supports "H (two of which are shown inFig. 2) are cast integrally with valve 55 to increase its strength andweight. The valve 55 is operatively coupled with one end of an actuatingmember 59. The actuating member is rigidly secured to a rock shaft 6!journaled to the side of the valve casing l l. The rock shaft El isrotated by a member 18 which is actuated by the mechanism indicatedgenerally by the reference numeral 53 in Fig. 1, but not shown in Figs.2, 3 0r 4 of the drawings.

The valve casing II is machined to permit the insertion of atubular-shaped insert 83. The insert 83 is made of high strengthmaterial and is retained in position Within the valve casing II bybrazing carefully only the outer periphery of the flange-shaped portion85 of the tubularshaped insert 83 to the casing II, using silver solder'33. In the brazing process particular pains are taken to obtain a goodbrazing job and still to prevent the silver solder 13, used in thebrazing process, from flowing into the small horizontal air gap,indicated by reference numeral 27, between the valve casing H and thetubularshaped insert 83, and also to insure the prevention of any silversolder flowing between insert 83 and valve casing II at the pointindicated by reference numeral 89. To accomplish this, strings ofasbestos, indicated by reference numeral iii, ar placed about the insert83 before it is inserted into the valve casing ll. Asbestos washers, notshown, could, of course, be used in place of the asbestos strings 9|.The friction between the valve seat insert 83 and the casing M tends todamp the oscillations on closing where the external valve mechanism doesnot sufliciently damp the oscillations.

The result of the valve construction illustrated in Fig. l and Fig. 2 isthat the tubular-shaped insert 83 is rigidly held to the valve casing llonly at the outer periphery of the flange-shaped portion 85. It is thusapparent that the tubular portion, indicated by reference numeral 93,and constituting the actual valve seat is free to move up and down underthe impact caused by the closing of valve 55.

Thus the insert 83, while being maintained in fixed relation to casing Hunder static conditions, will give sufficiently under high energy impactto provide the flexibility necessary to permit the valve seat to absorbthe energy Without permanent deformation. The stresses at the valve seatare reduced to such an extent that no permanent deformation of eitherthe valve 53 or the insert 83 is caused, and the valve always remainsgas tight. It will be noted that since insert 83 constitutes the valveseat, the material out of which the valve casing II is made is notimportant, the valve casing ll merely furnishing a foundation for theinsert 83, the latter of which takes the impact caused by valve 55closing.

It has been found that good results can be obtained without using silversolder but merely using soft solder. Silver solder is, however,preferable. The asbestos strings 9| or asbestos washers can be omittedentirely with good results. Their use, merely provides an insuranceagainst the possible flow of the solder T3. The air gap 61 may beincreased and a brass ring (not shown) placed between the flange portion85 of insert 83 and valve casing H. The brass, being resilient, will notimpede the resilient feature of the insert $3, and the use of a brassring is desirable where space is not at a premium, and a large air gap:between the insert 83 and the valve casing II is desired. The brassring gives some support to the valve seat portion or insert 83 yet doesnot affect the resilient operation of the insert 83 because of theresilient characteristic of the metal brass. The use of a brass ring isnot illustrated in the drawings, Fig. 1 and Fig. 2 merely showing anapplication of the invention where space is at a premium.

If the insert 83 is soldered to the valve casing H throughout its entirelength, that is, if the insert 83 is not only soldered to valve casing lI at the periphery of its flange portion 35, but also along the externaltubular portion 89, then naturally the insert 83 is entirely rigid withrespect to casing l i and the valve seat will be nonresilient and henceunsatisfactory. To get the good results obtained by the use of the valveconstruction illustrated Fig. 1 and Fig. 2, the valve seat portion ofinsert 83 must be resilient, and this requirement prohibits thesoldering of insert 83 to valve casing II at any place along thelongitudinal portion 93 of insert 83. It would. of course, be possibleto obtain the same good re sults produced by the valve construction in land Fig. 2 if more or less of the flange portion 85 were soldered tovalve casing ll the essential feature being that at least part of theflange portion 85 be soldered to valve casing Ii, the longitudinaltubular portion 93 remaining unsoldered and free to move longitudinally.

The novel valve construction illustrated in Fig. 1 and shown enlarged inFig. 2 has eliminated the problem present in previous valveconstructions, namely the prevention of permanent deformation of boththe valve and the valve seat under conditions of high speed. operationof the circuit interrupter. In previous valve constructions the highamount of kinetic energy stored in the rapidly moving valve would causea permanent deformation of both the valve and the valve seat. As aconsequence of such permanent deformation, the valve no longer wouldhold air or other gas satisfactorily. Making the valve and the valveseat of a higher strength alloy produced no apparent improvement in theoperation of the circuit interrupter. The dissipation of theconsiderable amount of kinetic energy stored up in the rapidly movingvalve in moving from the open to the closed position would causestresses and strains in the Valve and the valve seat, and would resultin a permanent deformation of both these members. A few operations ofthe circuit interrupter would cause the valve to leak air or other gas.The present invention removes the problems outlined above in previousvalve construc-tions. The circuit interrupter shown in Fig. 1 remainsgas tight even though the heavy parts move rapidly and even though theinterrupter has been subjected to many operations at high speed in lifetests.

Fig. 3 illustrates a modification of the present invention. Here a valvecasing 9-5 is so machined that there is provided a shoulder 91 uponwhich rests a flat spring washer 99. The energy of impact caused by thesudden stopping of the rapidly moving valve 55 is absorbed by thedeflection of this flat spring washer 99. To prevent air or gas leakagebetween the seat insert l0] and the valve casing 95, a thin steel orother flexible metallic ring M33 is provided. This thin steel ormetallic ring Hi3 has holes m5 bored near its in ner periphery, throughwhich pass screws Iii? which secure the metallic ring 23 to the valveseat insert IBI. A gasket of rubber or of a synthetic rubber such aspolymerized chloroprene or polymerized chlorobutadiene, or a gasket ofany flexible material, indicated by reference numeral I2 9, is usedunder metallic ring I03. Another gasket Hi, made of flexible resilientmaterial, is used between metal ring I93 and valve casing to prevent gasleakage The valve seat insert Hi l is made a press fit in the valve toreduce the oscillations occurring after impact. The damping of suchoscillations is caused by the friction between the insert NH and valvecasing 95. A press fit may not be necessary in some cases where theremay be suflicient damping in the valve mechanism itself to damp out theoscillations.

Instead of using the flat spring washer 89, one may use in its place aradially tapered spring washer, not'shown. Where space is at a premium,the flat spring washer 99 may be so bored that its inner periphery ishalf as thick its outer periphery. The shoulder H3 of insert [ill whichrests on the spring washer 953 may then be so machined that when thevalve is assembled, the overall height of the valve may be less than theconstruction illustrated in Fig. 3.

For one particular application of the construction illustrated in Fig.3, for a valve travel of /2 inch, a pressure differential of pounds persquare inch. and an energy to be a sorbed of 500 inch pounds, thecalculated dimensions of the fiat spring washer were as follows: Outerdiameter 5 /2 inches; inside diameter3% inches; thickness-V2 inch; thethickness of the thin steel ring to prevent leakageinch. By using thesedimensions, the peak impact load could be reduced to a small fraction ofthat occurring a solid valve seat.

Fig. 4 illustrates another modification of the present invention. Inthis modification the valve seat insert 5 i5 floats in position and isnot braved into place at any point, is it by screws 10, any thin washer.The insert H5 rests upon two elastic rings Ill and H9. When the valvecloses, the kinetic energy of the moving valve 55 is largely adsorbed intwo ways. First. the elastic rings Hi and H9 are compressed. and thiscompression absorbs considerable kinetic energy. Secondly, the insert H5itself acts as compression spring similar to the constructionillustrated in l and 2. Consequently, because of these two resilientfeatures of the construction illustrated in Fig. 4, there is nopermanent deformation of either the valve 55 or insert H5. The frictionbetween the insert H5 and the valve casing I23 tends to damp the oscillations on closing where the external valve mechanism does notsufficiently damp the oscillm tions.

It will be noted in 4 that the flange portion l2l of the insert H5 isextended outwardly considerably farther than in the other illustratedconstructions. By machining out of the flange portion l2| of insert H5 aretaining groove I23 and inserting therein a resilient ring-shapedgasket I 25, it is possible to have a gas-tight seal between the insert1 l5 and flange l2! of the conduit 9 leading out of the storage tank 1(not shown, in

Fig. 4). It will be observed that automatically there is also provided agas-tight seal between the valve casing I29 and the flange I21 ofconduit 9. By machining out a ridge I3I on the flange portion I21 ofconduit 9 and by placing a flexible ring-shaped gasket I33 outside theridge I3I, it will be seen that by tightening up on the flange bolts I35and the flange nuts I31, the ridge I3I will tend to bite into theretaining groove I23 of insert H and that both gaskets I25 and I33 willbe compressed. The result is a gas-tight joint. This construction makesit unnecessary to make the valve casing I29 out of expensive valvebronze in order to obtain an airtight casting I29 since the gas does notcome in contact with valve casting I29.

The difierent constructions illustrated in Figs. 2, 3 and 4 can be usedon any apparatus, not necessarily electrical, which uses valves andwhere the kinetic energies involved in the moving valve parts tend todeform the valve parts. The present invention is not confined in itsapplication to circuit interrupters. For purposes of illustration onlyhas the invention been applied to circuit interrupters.

Although we have shown and described specific structures, it is to beunderstood that the same were for the purpose of illustration and thatchanges and modifications may be made by those skilled in the artwithout departing from the spirit and scope of the appended claims.

We claim as our invention:

1. In a valve mechanism, a casing for said valve mechanism, a movablevalve, a seat for said valve, said seat comprising a tubular memberfrictionally engaging said casing to assist in damping the oscillationsduring the closing of said valve, an otfstanding supporting portion forsaid seat, the outer portion of said supporting portion remainingrelatively flxed in position with respect to the inner portion of saidsupporting portion adjacent said seat, the resiliency of said supportingportion being sufllcient to absorb the kinetic energy of said movablevalve when the latter is moved to the closed position withoutsubstantial deformation.

2. In a valve mechanism, a movable valve, a seat for said valve, a valvecasing, said seat comprising a tubular member frictionally engaging saidcasing to assist in damping the seat oscilla tions during closing,annular flanging means for resiliently supporting said seat, saidflanging means being of such width and so arranged that the outerportion thereof remains in a relatively fixed position with respect tothe inner portion thereof during closing of said valve, said flangingmeans being sufficiently resilient to absorb the kinetic energy of themoving valve during a closing operation without substantial deformation.

3. In a valve mechanism, a movable valve, a resiliently mounted seat forsaid valve, a valve casing, said seat comprising an elongated metallictubular member, said member having one end portion thereof frictionallyengaging said casing to damp the oscillations during closing, the otherend of said metallic tubular member forming the seat for said valve,metallic flanging means adjacent the seat end of said metallic tubularmember for resiliently supporting the same, said flanging means being sodisposed that the outer portion thereof remains relatively fixed inposition with respect to the inner portion thereof adjacent said seatduring closing of said valve, said hanging means being sufficientlyresilient to absorb the kinetic energy of said valve closing withoutbeing permanently deformed.

(i. In a valve mechanism, a movable valve and a resiliently mounted seattherefor, and means frictionally engaging said resiliently mounted seatto assist in damping the oscillations in said seat during the closingoperation of said valve.

5. In a valve mechanism, a housing for said valve mechanism, a movablevalve having considerable kinetic energy during the closing operation, aseat for said movable valve inserted within said valve housing, saidseat comprising a flanged member, said flanged member being soldered tosaid housing by the circumferential portion of its flange, an air gapbetween said housing and the flange portion of said member, and a damcircling the flange portion of said member to prevent solder flowing insaid air space.

6. In a valve mechanism, a casing for said valve mechanism, a movablevalve, a seat for said movable valve, said seat comprising a flangedmember inserted within said casing, a resilient washershaped element,said flanged member being resiliently supported by the flange portionthereof by means of said resilient washer-shaped element, and means forpreventing the medium passing through the valve mechanism from enteringthe space between the outer portion of said flanged member and saidcasing.

7. In a valve mechanism, a casing for said valve mechanism, a movablevalve, a seat for said movable valve, said seat comprising a flangedmember inserted within said casing, a metallic Washer-shaped element,said flanged member being resiliently supported at the flange portionthereof by said washer-shaped element, a thin washer-shaped metallicmember secured to the flange portion of said flanged member and alsopressed against said casing to prevent the medium passing through thevalve from entering the space between the casing and the outer portionof said flanged member.

8. In a valve mechanism, a valve casing forming a shoulder, a valve, aseat for said valve, said seat comprising a flanged member insertedwithin said casing, a ring-shaped spring member resting on the shoulderof said valve casing and supporting said flanged member by the flangeportion thereof, a thin washer-shaped member securely fastened to theflange portion of said flanged member and also pressed against saidcasing to prevent leakage of the medium passing through the valvebetween the flanged member and the valve casing.

9. In a valve mechanism, a valve, a valve casing, a seat for said valve,said seat comprising a flanged member inserted in said valve casing, oneor more resilient rings to support the flange portion of said flangedmember, said one or more resilient rings and said flanged member bothassisting in the formation of a resilient seat for said valve to absorbthe kinetic energy of the valve during closing.

10. In a valve mechanism, a flanged housing for said valve mechanism, aflanged conduit leading to said housing, a valve, a seat for said valve,said seat comprising a flanged tubular member inserted in said housing,said flanged tubular member being flexibly supported by the flangeportion thereof, said flanged tubular member having a groove cut in saidflange portion, flexible material placed in said groove, and means forsecuring said flanged conduit to said flanged housing and at the sametime compressing said flexible material placed in said groove to form agas-tight joint between said flanged conduit and said flanged tubularmember.

11. In a valve mechanism, a movable valve and a resiliently mounted seattherefor, a washershaped metallic member, said seat being resilientlysupported by said washer-shaped metallic member.

12. In a valve mechanism, a movable valve, a seat for said valve, saidseat comprising an annular member having a considerable flange portion,elastic means for supporting said member by the flange portion thereof,the flange portion and said elastic means both cooperating to rendersaid seat resilient to take up the shock on closing without permanentdeformation.

ARTHUR M. WAHL. FREDERICK B. JOHNSON.

